The present invention relates to an improvement in a digital video disk or digital versatile disk (DVD disk) capable of recording image and audio data on a signal recording medium and reproducing them in synchronism with each other, and a reproduction system therefor.
More particularly, the present invention relates to, in this system, an improved user interface in a DVD player capable of selectively and freely reproducing an image at an arbitrary angle desired by a user (viewer) in reproducing data from a DVD format disk capable of recording, in the form of a multiangle block, a set of images obtained by photographing or imaging a single scene (or a single event or a related event) at different angles.
Currently popular visual and audio recording media such as a compact disk (CD) and a laser disk (LD) have no idea of a multiangle block of "recording a set of images obtained by photographing or imaging a single scene at different angles". A title producer (provider) cannot produce or distribute such multiangle software (optical disk), even if wanted.
Even though an optical disk recorded with multiangle software were made, no user has a player having a multiangle reproduction function (such a player is not commercially available). Even if the provider wants to provide software using the multiangle function, there is no environment (infrastructure) for reproducing multiangle software.
Under these circumstances, a large-capacity DVD disk have been introduced initially called as a super density (SD) disk. The DVD has a special format which can realize the recording/reproducing function of the multiangle block. By this format, any provider can produce software using the multiangle function, can record such multiangle software on DVD disks, and distribute these DVD disks.
Further, in a video-on-demand system wherein contents of a DVD software including the multiangle block can be received by subscribers with certain charge (or with no-charge but with a commercial program), the provider can produce software using the multiangle function. Such software can be distributed to any subscriber of the video-on-demand system via digital lines, at the time when the subscriber demands such software.
In a player for reproducing a multiangle software (DVD disk) based on the above format, it is indispensable to reproduce the multiangle block. For this reason, any DVD player shall reproduce a disk on which the multiangle block is recorded, and has to allow an end user to freely select and reproduce an image with an angle desired by him or her.
Before the present invention has been made, there is no means for clearly notifying the user (viewer) whether or not he or she can voluntarily select a desired angle, or no means for clearly notifying the viewer whether or not the current scene allows an angle selection by the user (or whether or not the multiangle block is currently played back).
Further, (especially in a video-on-demand system,) no means is available to a user to easily instruct an angle change during the reproduction of the multiangle block.